1. Field of the Invention
This invention relates to a heat exchanger able to exchange heat between two fluids with extremely high efficiency.
2. Description of the Prior Art
In homes, offices, factories and the like, it is frequently found necessary to exchange heat between two fluids. For example, heat exchange is required between indoor and outdoor air during ventilation of air-conditioned rooms, between the intake and exhaust air of hot air driers, between supply water and waste water at factories and in many other situations.
The methods conventionally used for such heat exchange between two fluids, specifically between two gases, between two liquids or between a gas and a liquid, include the so-called radiator method in which a liquid is pumped through a long, winding pipe provided with many fins and a gas is blown onto it with a fan, the method in which two fluids are passed through alternate passages of a honeycomb structure made of thin sheet metal, and the method in which heat exchange is achieved through the medium of a rotating heat-absorbing body which is alternately inserted into two flow paths.
Each method has its disadvantages. The first requires a complex and expensive heat exchanger, the second achieves low heat exchange for its size owing to the use of immovable fins, and the third leads to some degree of mixing of the two fluids between which heat exchange is conducted. While in all three methods the temperature difference between the two fluids is smaller after heat exchange than before, in none of them does the high-low temperature relationship between the two fluids reverse. Defining the heat exchange efficiency in the case where the temperatures of two heat-exchanged fluids reverse as 100 (%), heat exchange efficiency by the conventional methods never exceeds 50 (%).